A central processing unit (CPU) cache is a cache used by CP of computing system to reduce the average time to access memory. The cache is a smaller, faster memory which stores copies of the data from frequently used main memory locations. Most CPUs have different independent caches, including instruction and data caches, where the data cache is usually organized as a hierarchy of more cache levels (L1, L2 etc.). For example, when the CPU needs to read or write data to a location in memory, it first verifies whether a copy of the data is in the cache. If so, the CPU immediately reads from or writes the data to the cache, which can be a faster process than reading from or writing the data to main memory.